Door drives comprising belt transmissions, belt transmissions, and doors operated by belt transmissions of the type mentioned above have been known for a long time in the most varied forms. The belt transmission may comprise a flat belt which is passed under tension around cylindrical pulleys, whereby the drive force is transmitted from the driven pulley to the belt by force or friction lock. Greater forces can be transmitted if V belts are used which are passed around grooved V belt pulleys (JP 2-173,436 A, Patent Abstracts of Japan, Vol. 14, No. 436, Sep. 18, 1990). It is likewise known to devise the transmission belt as a toothed belt for cooperation with a drive wheel provided with complementary teeth along its periphery (DD 238,093 A1; FR 1,379,737 A). Other comparable drive means operate with round belts, such as smooth steel cables which are guided around grooved pulleys, or steel cables on which balls or the like are fastened at certain intervals for engagement in complementary, grooves with cavities formed in corresponding guide wheels. Moreover, chain drives comprising suitable sprockets are used as door propelling means. Many of these measures are intended to warrant that the drive force is transmitted in form lock. The fields of application of these drive means partly differ from one another, while they overlap in other respects. The strengths and weaknesses, or the advantages and disadvantages, of all these drives are well known. Those skilled in the art likewise dispose of sufficient knowledge concerning materials which are suitable for flat belts, round belts, and V belts.